thumb|Yochelcionella cyrano thumb|Pelagiella atlantoides Helcionelloida is an extinct group of ancient molluscs (phylum Mollusca). These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.
thumb|Yochelcionella cyrano thumb|Pelagiella atlantoides Helcionelloida is an extinct group of ancient molluscs (phylum Mollusca). These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.
==Anatomy==
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).